A place where you can be 100% certain no one will hear you is ideal. When I want to practice talking I drive to an empty parking lot and read out loud in my car. The purpose is if you stutter, you’re the only person who will ever know, so it minimizes the frustration and embarrassment you’d normally feel. After doing this for over half a year now, I’m almost perfectly fluent when talking to myself. I’m not as fluent when talking to other people, but I’ve built up so much muscle memory that my conversational skills have vastly improved. Whenever I get frustrated and start stuttering, I think back to the times I talked in my quiet place and what it felt like to speak correctly, so I’m able to bounce back a lot quicker. If you absolutely can’t find a quiet place, then your apartment works too. Any amount of speech training is better than nothing.